How to till, please advise.

[lawn hopper]

Started tilling today after getting my tiller running.

Wondering how deep to till for creating a garden area on a turf area?
Till flower beds how deep? Does the answer depend on plant to be used? Do guys usually add black soil after tilling before a mix till. Any other pertinent info please advise.
Thanks
Ryan

[Ghost999]

tilling

I would say 6 to 8 inches should be good enough, till the area first then add your admendments,fertilizer, and retill.